Microelectromechanical system-based resonator device

Abstract

The disclosure provides a structure for a microelectromechanical system (MEMS)-based resonator device. The structure for the MEMS-based resonator device includes at least one resonator unit. The at least one resonator unit comprises a substrate having a trench therein. A pair of first electrodes is disposed on a pair of sidewalls of the trench. A piezoelectric material fills the trench, covering the pair of first electrodes. A second electrode is embedded in the piezoelectric material, separated from the pair of first electrodes by the piezoelectric material. The second electrode disposed in the trench is parallel to the pair of first electrodes.

What is claimed is: 
     
       1. A structure for a microelectromechanical system (MEMS)-based resonator device, comprising:
 at least one resonator unit, wherein the at least one resonator unit comprises:
 a substrate having a trench therein; 
 a pair of first electrodes disposed on a pair of sidewalls of the trench; 
 a piezoelectric material filling the trench, covering the pair of first electrodes; and 
 a second electrode embedded in the piezoelectric material, separated from the pair of first electrodes by the piezoelectric material, wherein the second electrode disposed in the trench is parallel to the pair of first electrodes. 
 
 
     
     
       2. The structure for the MEMS-based resonator device as claimed in  claim 1 , wherein the pair of first electrodes extends to the bottom surface of the trench, and wherein the first electrodes are connected to each other. 
     
     
       3. The structure for the MEMS-based resonator device as claimed in  claim 1 , wherein the substrate comprises:
 a handle layer; 
 a sensor-device layer disposed over the handle layer; and 
 an insulating layer disposed between the sensor-device layer and the handle layer. 
 
     
     
       4. The structure for the MEMS-based resonator device as claimed in  claim 3 , wherein the trench is disposed in the sensor-device layer, and the bottom surface of the trench is coplanar with the interface between the insulating layer and the sensor-device layer. 
     
     
       5. The structure for the MEMS-based resonator device as claimed in  claim 4 , wherein the substrate further comprises a trench filled with air through the sensor-device layer extending into the insulating layer, whereby the bottom surface of the pair of first electrodes, which is coplanar with the interface, is exposed to the trench filled with air. 
     
     
       6. The structure for the MEMS-based resonator device as claimed in  claim 5 , wherein the at least one resonator unit is floated over the handle layer. 
     
     
       7. The structure for the MEMS-based resonator device as claimed in  claim 1 , wherein the top surfaces of the pair of first electrodes, the top surface of the second electrode, and the top surface of the piezoelectric material are coplanar with the top surface of the substrate. 
     
     
       8. The structure for the MEMS-based resonator device as claimed in  claim 1 , wherein the at least one resonator unit further comprises:
 a pair of output electrodes disposed on the top surface of the substrate, respectively connected to the pair of first electrodes; and 
 an input electrode disposed on the top surface of the piezoelectric material, connected to the second electrode. 
 
     
     
       9. The structure for the MEMS-based resonator device as claimed in  claim 8 , wherein the pair of output electrodes is substantially perpendicular to the pair of first electrodes, and the input electrode is substantially perpendicular to the second electrode. 
     
     
       10. The structure for the MEMS-based resonator device as claimed in  claim 1 , wherein the second electrode is embedded in a central position of the piezoelectric material. 
     
     
       11. The structure for the MEMS-based resonator device as claimed in  claim 1 , wherein the direction of the electrode field generated between the pair of first electrodes and the second electrode is parallel to the direction of polarization of the piezoelectric material. 
     
     
       12. The structure for the MEMS-based resonator device as claimed in  claim 1 , wherein the second electrode extends from the top surface of the piezoelectric material to the bottom surface of the trench. 
     
     
       13. The structure for the MEMS-based resonator device as claimed in claim  1 , wherein the piezoelectric material of the at least one resonator unit is disposed in a central position thereof. 
     
     
       14. The structure for the MEMS-based resonator device as claimed in  claim 1 , wherein the at least one resonator unit is a plurality of the resonator units. 
     
     
       15. The structure for the MEMS-based resonator device as claimed in  claim 14 , wherein the plurality of resonator units is continuously arranged as a periodic structure, and wherein the period of the plurality of resonator units defines the operation frequency of the MEMS-based resonator device. 
     
     
       16. The structure for the MEMS-based resonator device as claimed in  claim 14 , wherein the substrates of the plurality of resonator units are Connected to each other.